Presentation on theme: "Balancing Chemical Equations"— Presentation transcript:
1 Balancing Chemical Equations Chapter 17 Section 2Balancing Chemical Equations
2 17.1 Products and reactants In chemical reactions, you start with reactants that are combined to make products.The reactants are the starting substances.The products are the new substances which result from the chemical reaction.
3 17.1 Reactants and products In the reaction, methane (a natural gas) is burned or combusted.Some energy is added to get the reaction started.
4 17.2 Conservation of massLavoisier showed that a closed system must be used when studying chemical reactions.When chemicals are reacted in a closed container, you can show that the mass before and after the reaction is the same.
5 17.2 Chemical EquationsWhen a chemical reaction is written using chemical formulas and symbols, it is called a chemical equation.
6 17.2 Chemical equationsAn arrow is always included between reactants and products.It means “to produce” or “to yield.”to produceReactantsProducts“Methane combines with oxygen gas to produce carbon dioxide gas and water vapor.”